Advice Needed UHF antenna coupling

[zorrin]

I don't know since when, but the frequency on which I received the Belgian multiplex has changed.
Now it's channel 55.
More interesting now I receive the channels permanently.
On my Sony TV the quality is very variable but on my AXAS HIS COMBO 4K the quality is very good.

A yes, I haven't changed the antennas yet...

 

[Adam792]

I don't know since when, but the frequency on which I received the Belgian multiplex has changed.
Now it's channel 55.
More interesting now I receive the channels permanently.
On my Sony TV the quality is very variable but on my AXAS HIS COMBO 4K the quality is very good.

A yes, I haven't changed the antennas yet...

View attachment 147667


View attachment 147668

Nice result! E55 is apparently from the Léglise/Vlessart transmitter which is 100kW -

https://fmscan.org/net.php?r=t&m=m&bouq=0&itu=BEL&pxf=la+une

It's probably much less likely, but considering where that transmitter is - it might be worth looking out for Luxembourg on E21/E24/E27! Obviously depends on what's co-channel though.

 

[zorrin]

Nice result! E55 is apparently from the Léglise/Vlessart transmitter which is 100kW -

View attachment 147671

https://fmscan.org/net.php?r=t&m=m&bouq=0&itu=BEL&pxf=la+une

It's probably much less likely, but considering where that transmitter is - it might be worth looking out for Luxembourg on E21/E24/E27! Obviously depends on what's co-channel though.

Unfortunately today nothing.
But from 6 p.m. to 11:30 p.m. I had the usual Belgian multiplex:
TV :
- La Une
- La Deux
- La Trois
- EuroNews

Radios :
- La Première
- VivaCité
- Musiq' 3
- Classic 21
- Pure FM
- BRF

I also had 3 French channels:
- France 3 Nord Pas de Calais
- France 3 Champagne-Ardenne
-MATELE

 

[zorrin]

Hello everyone.
I continued my antenna coupling project.



Question: Do I have to add a 75 ohm cap on the VHF input?

 

[Terryl]

You can if you want to, but make sure that the two cables from the antennas are of equal lengths.

And whats the spacing between the antennas?? It should be a 1/4, 1/2 or a full wavelength of the lowest frequency your looking at, or you may have problems.

https://www.everythingrf.com/rf-calculators/frequency-to-wavelength

 

[zorrin]

You can if you want to, but make sure that the two cables from the antennas are of equal lengths.

And whats the spacing between the antennas?? It should be a 1/4, 1/2 or a full wavelength of the lowest frequency your looking at, or you may have problems.

https://www.everythingrf.com/rf-calculators/frequency-to-wavelength

Yes both cables are the same length.
For the base frequency I took 470MHz or 63.7cm between the two antennas.
Fortunately, these two pieces of information have already been given to me on the previous pages.

 

[zorrin]

The hardest thing to find was the rotor...
The gears break, the plastic becomes brittle.

 

[zorrin]

I no longer pick up the "traces" of Belgian TV.
I believe that the switch to DVB-T2 was not good for me...
But I picked up other "traces"...
I did not make a screenshot or retrieve the frequencies unfortunately but I found where they came from.
channel names were followed by "(connect)"

CNN Int. (connect)
tv.berlin (connect)
I found on a video the same names followed by connect


It's probably a German transmitter but I can't find any info on the net.
Any idea ?

 

[Adam792]

I no longer pick up the "traces" of Belgian TV.
I believe that the switch to DVB-T2 was not good for me...
But I picked up other "traces"...
I did not make a screenshot or retrieve the frequencies unfortunately but I found where they came from.
channel names were followed by "(connect)"

CNN Int. (connect)
tv.berlin (connect)
I found on a video the same names followed by connect
View attachment 151320

It's probably a German transmitter but I can't find any info on the net.
Any idea ?

No sign of channel 56 (DVB-T) or 42 (DVB-T2) from Belgium now then? Apparently both are on-air for now during a switchover period.

That multiplex with the (connect) and ZDF/3Sat/KiKA services is the national ZDF/Freenet DVB-T2 mux from Germany - do you know what channel/frequency it was on?

 

[zorrin]

No sign of channel 56 (DVB-T) or 42 (DVB-T2) from Belgium now then? Apparently both are on-air for now during a switchover period.

That multiplex with the (connect) and ZDF/3Sat/KiKA services is the national ZDF/Freenet DVB-T2 mux from Germany - do you know what channel/frequency it was on?

The "traces" are discovered by my SONY TV which must have an automatic update function.
I have to deal with the French channels which also use frequencies...
For the moment it is my "normal" antenna which is used.
It was to have a dedicated antenna that I embarked on this project.

 

[zorrin]

No sign of channel 56 (DVB-T) or 42 (DVB-T2) from Belgium now then? Apparently both are on-air for now during a switchover period.

That multiplex with the (connect) and ZDF/3Sat/KiKA services is the national ZDF/Freenet DVB-T2 mux from Germany - do you know what channel/frequency it was on?

I don't have the frequency...
I hope to get it back

 

[Channel Hopper]

I don't have the frequency...
I hope to get it back

Most modern TV digital tuners will have a signal level check which looks at the specific channel selected..

 

[zorrin]

I need your help...
I had finished the preparations.
I was ready to install the rotor and antennas and found this...



Une TELEVES PRO75 avec un MRD5050



Here are my questions.
Do you think like me that it is preferable to use the pro75 rather than the coupled antennas?

Does the MRD5050 replace an antenna preamplifier or should I add one too?

 

[Adam792]

Not sure, looking online it seems like the gain for that antenna is listed as 19 dBd, which is likely to be the peak figure at the top of the UHF band (unfortunately the area now filled with 5G instead of TV signals!)

Channel 55/56 in Wallonia switched off on 31st August, with channel 42 in DVB-T2 now being the only signal available -

https://twitter.com/i/web/status/1697233962098159645

 

[PaulR]

I think those are known as slope gain antennas. The gain is most at the highest frequencies where the loss is greatest. There should still be gain down at the bottom end though.

It might be an idea to put a bandpass filter of some kind in place so that you're not amplifying high powered mobile phone traffic. Is there a cell station near you?

 

[zorrin]

I think those are known as slope gain antennas. The gain is most at the highest frequencies where the loss is greatest. There should still be gain down at the bottom end though.

It might be an idea to put a bandpass filter of some kind in place so that you're not amplifying high powered mobile phone traffic. Is there a cell station near you?

That's only part of the problem...
If the MRD5050 is a preamplifier it seems to me that I cannot add another one that would have a 5G filter.
In this case I can use a 5G filter alone like this one



I really need to find out if I can put a preamp or not, use the MRD or not...

 

[zorrin]

Not sure, looking online it seems like the gain for that antenna is listed as 19 dBd, which is likely to be the peak figure at the top of the UHF band (unfortunately the area now filled with 5G instead of TV signals!)

Channel 55/56 in Wallonia switched off on 31st August, with channel 42 in DVB-T2 now being the only signal available -

https://twitter.com/i/web/status/1697233962098159645

After reading your post I tested my reception on channel 42.
FYI there is a multiplex on this frequency coming from the Eiffel Tower.
Usually I don't have any reception problems on this frequency.
But here I have a signal level at 100% and the quality at 5%...
with an antenna towards Paris and another towards Belgium on the same cable it seems to me that there is now a problem.

I had already decided to modify my installation in depth.

No more single cable for the two antennas, each will have a dedicated cable on separate and filtered inputs.

For the Belgium part, a specific cable and a specific filter too.

I am going to remove the arrival of channel 42 from Paris in case I manage to get to Belgium often.
With the ghostly traces of German channels, I told myself that there might be other things to catch from home.
It is therefore necessary to be able to filter at several levels.

but before that, I have to validate the options for the new antenna...

 

[Adam792]

After reading your post I tested my reception on channel 42.
FYI there is a multiplex on this frequency coming from the Eiffel Tower.
Usually I don't have any reception problems on this frequency.
But here I have a signal level at 100% and the quality at 5%...
with an antenna towards Paris and another towards Belgium on the same cable it seems to me that there is now a problem.

I had already decided to modify my installation in depth.

No more single cable for the two antennas, each will have a dedicated cable on separate and filtered inputs.

For the Belgium part, a specific cable and a specific filter too.

I am going to remove the arrival of channel 42 from Paris in case I manage to get to Belgium often.
With the ghostly traces of German channels, I told myself that there might be other things to catch from home.
It is therefore necessary to be able to filter at several levels.

but before that, I have to validate the options for the new antenna...

The Belgian signals (and also a lot of the German DVB-T2 signals) are in vertical polarisation too, which should help at least a bit - with the French services being horizontally polarised.

 

[Channel Hopper]

I need your help...
I had finished the preparations.
I was ready to install the rotor and antennas and found this...

View attachment 151636

Une TELEVES PRO75 avec un MRD5050

View attachment 151637

Here are my questions.
Do you think like me that it is preferable to use the pro75 rather than the coupled antennas?

Does the MRD5050 replace an antenna preamplifier or should I add one too?

I think you need to invest in a spectrum analyser that works up to 1GHz. Second hand, functional but uncalibrated it should give you an idea of what is bleeding into your specific frequencies of interest under 750MHz.

 

[zorrin]

I think you need to invest in a spectrum analyser that works up to 1GHz. Second hand, functional but uncalibrated it should give you an idea of what is bleeding into your specific frequencies of interest under 750MHz.

As I am high up facing the north of France I believe that the spread is significant.
But also depending on the weather.
You are right, what follows is a more in-depth analysis of the spectrum.
I think I don't see everything at the moment.